Headline
CVE-2023-20057: Cisco Security Advisory: Cisco Email Security Appliance URL Filtering Bypass Vulnerability
A vulnerability in the URL filtering mechanism of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to bypass the URL reputation filters on an affected device. This vulnerability is due to improper processing of URLs. An attacker could exploit this vulnerability by crafting a URL in a particular way. A successful exploit could allow the attacker to bypass the URL reputation filters that are configured for an affected device, which could allow malicious URLs to pass through the device.
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Summary
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A vulnerability in the URL filtering mechanism of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to bypass the URL reputation filters on an affected device.
This vulnerability is due to improper processing of URLs. An attacker could exploit this vulnerability by crafting a URL in a particular way. A successful exploit could allow the attacker to bypass the URL reputation filters that are configured for an affected device, which could allow malicious URLs to pass through the device.
There are no workarounds that address this vulnerability.
This advisory is available at the following link:
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-esa-url-bypass-WbMQqNJh
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Affected Products
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At the time of publication, this vulnerability affected all releases of Cisco AsyncOS Software for Cisco ESA.
See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information.
Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.
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Workarounds
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- There are no workarounds that address this vulnerability.
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Fixed Software
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When considering software upgrades, customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories page, to determine exposure and a complete upgrade solution.
In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.
Fixed Releases
For information about fixed software releases, see the Details section in the bug ID(s) at the top of this advisory.
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Exploitation and Public Announcements
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- The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
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Source
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- Cisco would like to thank Roy Barkay Yosef and Chen Farchi for reporting this vulnerability.
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Cisco Security Vulnerability Policy
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- To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
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Related to This Advisory
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URL
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Revision History
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Version
Description
Section
Status
Date
1.0
Initial public release.
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Final
2023-JAN-18
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Legal Disclaimer
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